1. Field of the Invention
The present invention relates to a method and apparatus for copying or moving digital contents between a device and a portable storage device, and more particularly, to a method and apparatus for copying or moving rights object having right information regarding digital contents between a device and a portable storage device without an error.
2. Description of the Related Art
Recently, digital rights management (DRM) has been actively researched and developed. Commercial services using DRM have already been used or will be used. DRM needs to be used because of the following various characteristics of digital content.
That is to say, unlike analog data, digital contents can be copied without loss and can be easily reused, processed, and distributed, and only a small amount of cost is needed to copy and distribute the digital content.
However, a large amount of cost, labor, and time are needed to produce the digital contents. Thus, when the digital contents is copied and distributed without permission, a producer of the digital contents may lose profit, and enthusiasm for creation may be discouraged. As a result, development of digital contents business may be hampered.
There have been several efforts to protect digital contents. Conventionally, digital contents protection has been concentrated on preventing non-permitted access to digital contents, permitting only people paid charges to access the digital content.
Thus, people who paid charges to the digital contents are allowed access to unencrypted digital contents while people who did not pay charges are not allowed access. In this case, when a person paid charges intentionally distributes the digital contents to other people, however, the people can use the digital contents without paying charges. To solve this program, DRM was introduced. In DRM, anyone is allowed to freely access encoded digital content, but a license referred to as a rights object is needed to decode and execute the digital content.
Accordingly, the digital contents can be more effectively protected by using DRM.
A portable storage device is a connectable/disconnectable device such as a portable phone, a computer, or a digital camera which can store data of various types of digital equipment and is portable. The portable storage device includes a storage space for storing data and a portion performing an operation and control. A multimedia card (MMC) is a portable storage device and stores multimedia data to be used for various types of digital equipment, overcoming limitations of conventional hard disks or compact disks. The MMC also includes an operation part that is not included in conventional storage media, thereby having ability to perform control. As a result, the MMC is suitable to accommodate various kinds of multimedia data in large capacities. Recently, a security function has been added to the MMC, thereby developing a secure MMC that secures digital contents during storage and transmission and protects copyright. With the development of the secure MMC, rights management on digital contents becomes possible in a storage device and digital equipment. Hereinafter, digital equipment such as a digital camera, a portable phone, a computer, and a digital camcorder will be generally referred to as a “device.”
Currently, standard open mobile alliance (OMA) DRM is DRM defined by an OMA for the field of mobile technology. The OMA DRM has been suggested as standard DRM for data of digital contents downloaded to a mobile device such as a mobile phone. However, all digital data is not always moved or transmitted only from a server to a mobile phone. Digital data may be transmitted via a portable storage device. In addition, devices, e.g., digital cameras and computers, other than mobile devices usually transmit data via the portable storage device instead of using a mobile mode. Accordingly, development of DRM that covers technological characteristics of the OMA DRM and is suitable for portable storage devices is desired.
The concept of digital rights management (DRM) will be described with reference to FIG. 1. DRM relates to management of contents (hereafter, referred to as encrypted contents) protected using a method such as encryption or scrambling and rights objects allowing access to the encrypted contents.
Referring to FIG. 1, a DRM system includes user devices 110 and 150 wanting to access content protected by DRM, a contents issuer 120 issuing content, a rights issuer 130 issuing a rights object containing a right to access the content, and a certification authority 140 issuing a certificate.
In operation, the user device 110 can obtain desired contents from the contents issuer 120 in an encrypted format protected by DRM. The user device 110 can obtain a license to play the encrypted contents from a rights object received from the rights issuer 130. Then, the user device 110 can play the encrypted contents. Since encrypted contents can be circulated or distributed freely, the user device 110 can freely transmit the encrypted contents to the user device 150. The user device 150 needs the rights object to play the encrypted contents. The rights object can be obtained from the rights issuer 130. Meanwhile, the certification authority 140 issues a certificate indicating that the contents issuer 120 is authentic and the user devices 110 and 150 are authorized devices. The certificate may be embedded into devices used by the user devices 110 and 150 when the devices are manufactured and may be reissued by the certification authority 140 after a predetermined duration has expired.
DRM protects the profits of those producing or providing digital contents and thus may be helpful in activating the digital contents industry. Although a rights object or encrypted contents can be transferred between the user devices 110 and 150 using mobile devices, it is inconvenient as a practical matter. To easily move a rights object or encrypted content between devices, the efficient copying or moving of data between a device and a portable storage device acting as an intermediate between devices is desired. In addition, to prevent data copying or moving via a portable storage device from violating copyright, a method of managing copying and moving of a rights object is desired. Moreover, a method of controlling a sequence of commands used to move a rights object is desired to prevent loss of information or addition of information by an unauthorized input.